Many people may misunderstand the basics about opioids. That prevents researchers from understanding the full scope of the epidemic.

Sirley Silveira Paixao, an immigrant from Brazil seeking asylum, kisses her 10-year-old son Diego Magalhaes, after he is released from immigration detention in Chicago on July 5, 2018.
(AP Photo/Charles Rex Arbogast, File)September 19, 2018